Indonesian crab-eating macaques are favored by medical researchers. But if Miami primate dealer Matthew Block's late-August shipment was bound for the lab, it never got that far.

August 20 was a typically steamy Thursday in Miami, before anyone was paying much attention to a tropical storm called Andrew gathering in the Caribbean. Right on time, at 6:03 p.m., Lufthansa Airlines Flight 462 from Frankfurt, Germany, carrying 282 passengers, taxied up to gate E-23 at Miami International Airport and began unloading.

In the front cargo bay of the Boeing 747 sat 22 wooden crates holding 110 crab-eating macaques, small Southeast Asian monkeys favored in the United States as biomedical research subjects. This was the last leg of their journey that had started the day before in Jakarta, Indonesia. As with all of Lufthansa's monkey shipments out of Jakarta, this one awaited clearing by U.S. Customs, the U.S. Fish and Wildlife Service, and, through the Centers for Disease Control (CDC), the U.S. Public Health Service. The animals were to be quarantined for 31 days at Worldwide Primates, the firm on NW 53rd Street that imported them.

But from the moment the first cargo handler reached the crates, it was clear something was wrong. "Usually the animals would be sitting up and you could see their heads through the screen [in the crates]. There was no movement in any of the crates," says Tom DeMarcus of the CDC's quarantine division in Atlanta. When the boxes were finally opened -- by law, this must be done inside a quarantine facility -- it was only a confirmation of what the inspectors already knew: all 110 monkeys were dead. Aside from nasal hemorrhaging, there was little outward sign of what had caused their demise.

Fish and Wildlife agents noted the deaths on the agency's importation forms; a veterinarian was immediately called in by the importer to examine the carcasses. Tissue samples were sent for autopsy to the state diagnostic laboratory at Kissimmee and to Tulane University Medical Center in Covington, Louisiana. Finally, the corpses were wrapped in double layers of plastic and labeled as "medical waste" to be incinerated.

All part of an unremarkable response to an extraordinary incident: neither animal rights advocates nor regulatory officials can recall an entire shipment of primates ever arriving dead in the U.S. before, and few losses of this magnitude have been documented. But three days later Hurricane Andrew struck South Florida. If anyone intended to publicly tell the tragedy of the monkeys, a far grander disaster intervened.

The deaths may never have come to light if animal rights activist Shirley McGreal hadn't received a tip almost two weeks ago from one of her legion of worldwide contacts. "I wish we knew a lot more about it," says McGreal, chairwoman of the International Primate Protection League, based in Summerville, South Carolina. "We only learned by accident -- no government official told anybody, there was no public announcement."

Government agencies, the airline, and the importer all say they agree with McGreal that the deaths were highly unusual and that they wish they knew more about what killed the monkeys. But no one connected with the incident has much more to say about it.

"The only thing I can tell you is the case is under investigation," says Jorge Enrique Picon, the Fish and Wildlife Service's senior resident agent in Miami. The service is charged with enforcing federal regulations governing humane shipment of primates and would thus take action if a violation were found to have caused the monkeys' deaths. No agent actually saw the monkeys, however, Picon says; the service's personnel at the Miami airport aren't able to physically inspect each animal shipment that comes in, and a CDC inspector was on hand. Fish and Wildlife, CDC, and Lufthansa spokesmen all say they have no photographs of the monkeys.

The macaques -- dusky, wide-eyed creatures weighing less than five pounds on average -- were alive in Jakarta, and they were still alive when they were loaded onto Flight 462 in Frankfurt. Somewhere between Frankfurt and Miami, something killed them. It was not an infectious disease, according to Dr. Richard L. Miller, the Fort Lauderdale veterinarian hired by Worldwide Primates to perform autopsies on the monkeys. The CDC, responsible for determining whether any disease communicable to humans was involved, has no indication there is any cause for concern, says DeMarcus. Miller's examinations and test results from the labs showed evidence of shock and stress, possibly heat stroke, but no sign of illness or infection.

"Something happened en route that would cause them to go into immediate life-threatening situations, such as extremes of temperature or inappropriate ventilation," says Miller. "As to exactly what happened, I can't say." Poisoning of the monkeys' food and water supply is unlikely, he thinks; he'd expect to see at least some of the animals still alive on arrival. He declined to describe their appearance or to speculate more specifically about other possible causes of death. But while he has seen other primates who have died from shock and heat stress in the course of his thirteen-year practice, Miller says that "this is my first experience with this kind of situation."

Lufthansa spokesman Dan Lewis says it's a first for the airline, too. "We've been shipping monkeys for the past two or three years, about two shipments per month out of Jakarta, and we've not had any problems." Lufthansa was the official airline for the U.S. equestrian team during the last Olympics, Lewis adds, and is a recognized expert in transporting exotic animals, including the endangered black rhinoceros. Unlike horse and rhino flights, however, he adds, no veterinarian was on board with the macaques.